While scientists have been able to successfully clone animals, it remains to be seen how the genetic lineage of the subjects ill be altered. Already, we have heard reports that "Dolly", the cloned sheep, is weaker than the original, and has suffered through a series of illnesses, including arthritis.http://www.extinctanimal.com/cloning.htm

About one quarter of the species found as fossils in the caves are totally extinct. Of these species, most died out during the Pleistocene, 40 to 50 thousand years ago, while others became extinct following European settlement. Visit this website to find out more.http://www.environment.sa.gov.au/parks/naracoorte/wonambi/animals/extinct/